In many cases, a portable terminal device having a jog dial switch or shuttle switch is operated by a different method from that of a so-called desktop terminal device. The desktop terminal device mainly uses a keyboard or mouse as an input device, whereas the portable terminal device is operated by a pen input or button input. In recent years, input devices such as a shuttle switch and jog dial switch for enabling rotation operation and push operation with one device are becoming available.
The input devices such as a shuttle switch and jog dial switch are used for operations such as switching of the menu and scroll of the display window. This provides the user with high operability because rotation operation or slide operation directly and readily links with an operation on the display window.
The portable terminal device is generally used in the user's hand. Because of a small size, a terminal device whose screen is generally vertically directed can be used with a horizontally elongated screen, and vice versa. In this case, the display direction of the display window is also switched.
In this case, however, the rotational direction of the shuttle switch or jog dial does not coincide with the operating direction on the display window, which has not been considered. This will be exemplified with reference to FIG. 3.
In FIG. 3, when the portable terminal device is used with a vertically elongated screen 4000, rotation operation of a jog dial 406 is vertical rotation operation for the user. When the portable terminal device is used with a horizontally elongated screen 4100, rotation operation of the jog dial 406 is horizontal rotation operation for the user. For example, rotation operation of the jog dial 406 is assigned to vertical scroll of the vertically elongated screen 4000. In this case, even if the user horizontally rotates the jog dial 406 in use with the horizontally elongated screen 4100, the screen is vertically scrolled. The conventional user-friendly device makes the user feel the operation difficult.